text: /****************************************************************************
  **
  ** Copyright (C) 2017 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the QtQuick module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:LGPL$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** GNU Lesser General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU Lesser
  ** General Public License version 3 as published by the Free Software
  ** Foundation and appearing in the file LICENSE.LGPL3 included in the
  ** packaging of this file. Please review the following information to
  ** ensure the GNU Lesser General Public License version 3 requirements
  ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
  **
  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU
  ** General Public License version 2.0 or (at your option) the GNU General
  ** Public license version 3 or any later version approved by the KDE Free
  ** Qt Foundation. The licenses are as published by the Free Software
  ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
  ** included in the packaging of this file. Please review the following
  ** information to ensure the GNU General Public License requirements will
  ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
  ** https://www.gnu.org/licenses/gpl-3.0.html.
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/
  
  #ifndef QQUICKTAPHANDLER_H
  #define QQUICKTAPHANDLER_H
  
  //
  //  W A R N I N G
  //  -------------
  //
  // This file is not part of the Qt API.  It exists purely as an
  // implementation detail.  This header file may change from version to
  // version without notice, or even be removed.
  //
  // We mean it.
  //
  
  #include "qquickitem.h"
  #include "qevent.h"
  #include "qquicksinglepointhandler_p.h"
  #include <QtCore/qbasictimer.h>
  
  QT_BEGIN_NAMESPACE
  
  class Q_AUTOTEST_EXPORT QQuickTapHandler : public QQuickSinglePointHandler
  {
      Q_OBJECT
      Q_PROPERTY(bool pressed READ isPressed NOTIFY pressedChanged)
      Q_PROPERTY(int tapCount READ tapCount NOTIFY tapCountChanged)
      Q_PROPERTY(qreal timeHeld READ timeHeld NOTIFY timeHeldChanged)
      Q_PROPERTY(qreal longPressThreshold READ longPressThreshold WRITE setLongPressThreshold NOTIFY longPressThresholdChanged)
      Q_PROPERTY(GesturePolicy gesturePolicy READ gesturePolicy WRITE setGesturePolicy NOTIFY gesturePolicyChanged)
  
  public:
      enum GesturePolicy {
          DragThreshold,
          WithinBounds,
          ReleaseWithinBounds
      };
      Q_ENUM(GesturePolicy)
  
      explicit QQuickTapHandler(QObject *parent = nullptr);
      ~QQuickTapHandler();
  
      bool isPressed() const { return m_pressed; }
  
      int tapCount() const { return m_tapCount; }
      qreal timeHeld() const { return (m_holdTimer.isValid() ? m_holdTimer.elapsed() / 1000.0 : -1.0); }
  
      qreal longPressThreshold() const;
      void setLongPressThreshold(qreal longPressThreshold);
  
      GesturePolicy gesturePolicy() const { return m_gesturePolicy; }
      void setGesturePolicy(GesturePolicy gesturePolicy);
  
  Q_SIGNALS:
      void pressedChanged();
      void tapCountChanged();
      void timeHeldChanged();
      void longPressThresholdChanged();
      void gesturePolicyChanged();
      void tapped();
      void singleTapped();
      void doubleTapped();
      void longPressed();
  
  protected:
      void onGrabChanged(QQuickPointerHandler *grabber, QQuickEventPoint::GrabState stateChange, QQuickEventPoint *point) override;
      void timerEvent(QTimerEvent *event) override;
      bool wantsEventPoint(QQuickEventPoint *point) override;
      void handleEventPoint(QQuickEventPoint *point) override;
  
  private:
      void setPressed(bool press, bool cancel, QQuickEventPoint *point);
      int longPressThresholdMilliseconds() const;
      void connectPreRenderSignal(bool conn = true);
      void updateTimeHeld();
  
  private:
      bool m_pressed;
      GesturePolicy m_gesturePolicy;
      int m_tapCount;
      int m_longPressThreshold;
      QBasicTimer m_longPressTimer;
      QElapsedTimer m_holdTimer;
      QPointF m_lastTapPos;
      qreal m_lastTapTimestamp;
  
      static qreal m_multiTapInterval;
      static int m_mouseMultiClickDistanceSquared;
      static int m_touchMultiTapDistanceSquared;
  };
  
  QT_END_NAMESPACE
  
  QML_DECLARE_TYPE(QQuickTapHandler)
  
  #endif // QQUICKTAPHANDLER_H
  